If your site has less < 5,000 users a month, I can't imagine exceeding Lambda's free tier limit. You definitely want to go serverless if budget's a constraint.
the next question is whether I should have just one lambda call that gets my external data and serves it to the clientside requester
or if I should have one lambda that does gets my external data on a timed job, caches the response in a database, and a separate lambda that reads the response
on AWS it seems the databases are the most expensive thing
guess I could also just cross that bridge when I get there, just feel like I could get spammed to a big bill even if I put in some session variables client side
this is just a static website trying to power a data visualization on semi-live data